Leaching axial dispersion

S. Zaman, Single Column Leaching and Axial Dispersion Tests, Internal Report, Department or... 

Solutions for Pick s Second Law for leaching, in which extract with a constam inlet concentration Yf, passes through a fixed bed of solids initially cotttaining a uniform solid concentration Xi), have been developed by Rosen, Babcock et al., Neretniecks. and Rasmtssen and Neretniecks. Rosen s solutions apply only when is negligibly small the other solutions mice axial dispersion into account. These solutions can be used to determine S = (Y - MX,)l(Yi, - MX at time /. When r, > 50 Rosen indicates that... 

Marked axial dispersion in both the liquid and solid phases has been observed in continuous countercurrent leaching systems. The solid-phase dispersion is probably caused by nonuniform conveying and by backmixing caused by the baffles which are used to prevent solid beds from turning en masse. VnliD n values of 16.1 m and 20 m, respectively, have b n repotted for sugar beet extraction in tower and slope extractors. Local fiow nonuniformity and larger-scale flow maldistribution are the primary factors that cause axial dispersion in the extract. 

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